Commonly-assigned, Netherlands application, Ser. No. PHN 17 233, filed Dec. 17, 1998, and Netherlands application, Ser. No. PHN 17607, filed Sep. 19, 1999 both relate to light generators having one-piece lens arrays for collimating light.
This invention relates to lenses used for collimating and focusing light in LED light generators and in particular, to one-piece lens arrays for collimating and focusing light and LED light generators that use such lens arrays.
Present LED light generator designs collect light from an array of separate LED sources, and focus the light at a target, such as the entrance aperture of an optical fiber. A critical aspect in most of these designs is the collimation and focusing of the separate LED sources in order to create a useable light beam.
Many LED light generator designs employ a plurality of separate and distinct primary optical elements (collimators) each of which efficiently captures the widely divergent light generated by a respective one of the LED sources. For practical reasons, the collimators are identical, and thus have parallel optic axes which produce collimated light beams which are parallel to one another. A second lens (collection lens) focuses the parallel collimated light beams at the desired target. The second lens must have relatively high-angle refraction to focus the light beams generated by the LED sources at the periphery of the array.
The use of a separate and distinct collimator for each LED source of the array undesirably increases the size, complexity and cost of the light generator design. This is because the collimators must be individually mounted and aligned using bulky mounting hardware and spacers that require expensive handling and alignment steps during assembly.
Additionally, the high-angle refraction of the collection lens reduces total collection efficiency due to Presnel loss and beam spreading at the higher refraction angles.
Accordingly, lenses which collimate and/or focus light in LED light generators are needed that reduce handling and alignment during light generator assembly and allow more compact light generator packaging with substantially identical optical function.
In one aspect of the invention, a lens array for a lamp directs light to a light conduit such as an optical fiber or light pipe for guiding light to a remote location. An array of LED serve as light sources. The lens array includes an integrally formed member having a number of collimator lenses positioned in the lens array so that each lens can operate as a collimator for a corresponding LED to produce a respective collimated beam of light. The lenses have optical properties that are optimized according to where their corresponding LED are positioned in the LED array, so that the lens array is provided with lens prescriptions that produce refraction of the collimated beams of light toward an entrance aperture of the light conduit.
In another aspect of the invention, a light generator for a lamp uses an array of LED as light sources. Each LED generates diverging light. An integrally formed member defines a number of collimator lenses positioned in a lens array so that each of the lenses operates to collimate the diverging light generated by corresponding one of the LED into a respective collimated light beam. The lenses have optical properties that are optimized according to where their corresponding LED are positioned in the LED array. A collection lens is used for focusing the collimated light beams at an entrance aperture of a light conduit such as an optical fiber or light pipe.